New homochiral bis(oxazoline) ligands for asymmetric catalysis
1997; Elsevier BV; Volume: 8; Issue: 22 Linguagem: Inglês
10.1016/s0957-4166(97)00499-0
ISSN1362-511X
AutoresOlivier Hoarau, Hassan Aït‐Haddou, Michael De Castro, G.G.A. Balavoine,
Tópico(s)Synthetic Organic Chemistry Methods
ResumoSeveral homochiral bis(oxazolines), with asymmetric centers on the oxazoline rings and on the side chains, were prepared from (1S,2S)-(+)-2-amino-1-phenyl-1,3-propanediol in high yields. Asymmetric cyclopropanation of styrene with ethyl diazoacetate in the presence of 1 mol% of copper(I) triflate and the dibenzoyl bis(oxazoline) 5a. gave ethyl 2-phenylcyclopropanecarboxylate in up to 85% ee. The same ligand 5a, was used in the palladium catalysed enantioselective allylic substitution of the 1,3-diphenyl-2-propenyl acetate to give the desired product in up to 90% ee.
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